Substance can clean up marsh, Lake Simcoe: conservation authority

Substance can clean up marsh, Lake Simcoe: conservation authority

News

Improving water quality
By: Sandra Bolan

Phoslock can remove 87 to 95 per cent of phosphorus from the Holland Marsh without affecting water quality, according to the Lake Simcoe Region Conservation Authority.

“It’s very safe to use and there are no negative impacts associated with its use,” Mike Walters, director of watershed management for the Lake Simcoe Region Conservation Authority, said. “Because it takes nutrients out, it’s a great control for blue-green algae and other algae that form,” in lakes and rivers.

Phoslock, which is a natural precipitant, is dumped into the water prior to pumping. The Phoslock absorbs the phosphorus, then binds to a modified lanthanum-enriched clay to form an insoluble complex. That clay particle then settles on the bottom of the river, creating a 1 mm to 3 mm layer.

“It’s not the end-all and be-all, but a remedial quick fix,” until a more permanent solution can be found, Mr. Walters said.

“We haven’t been able to find a downside yet. There is no indication it is going to become a problem along the bank” and affect crops, he said.

The Phoslock also continues to work for a few weeks following its application.

For years, the Holland Marsh has been plagued with an over-abundance of phosphorus in its water, which has often been blamed for the poor water quality of Lake Simcoe.

A study in 2005 by the conservation authority noted a 20-year plan for treating the phosphorus in the marsh would cost $25 million.

However, using Phoslock in the marsh would cost $81,250 per application and Mr. Walters recommended the marsh receive two applications — one in the spring and another in the fall.

The Province of Ontario, Environment Canada and Fisheries and Oceans Canada have all approved the pilot project, according to Mr. Walters, who made a deputation to Bradford West Gwillimbury’s council last week looking for municipal buy-in.

Council did not make a decision.

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